MIAMI (AP) — Diana Nyad’s 110-mile swim from Cuba to Florida has generated positive publicity and adoration for the 64-year-old endurance athlete — along with skepticism from some members of the small community of marathon swimmers who are questioning whether she accomplished the feat honestly.

On social media and the online Marathon Swimmers Forum, long-distance swimmers have been debating whether Nyad got a boost from the boat that was accompanying her — either by getting in it or holding onto it — during a particularly speedy stretch of her swim. They also question whether she violated the traditions of her sport — many follow strict guidelines known as the English Channel rules — by using a specialized mask and body suit to protect herself from jellyfish.

“When you know how hard it is, you kind of want those details,” said Andrew Malinak, a Seattle long-distance swimmer who crunched the data available from the GPS positions tracked on Nyad’s website and concluded that he didn’t trust what he saw.

Nyad’s navigator and one of the swim’s official observers told The Associated Press this weekend that Nyad didn’t cheat and that she was aided during the rapid part of her swim by a swift current. And neither Nyad nor her team ever said she would follow English Channel rules, developed for swimming the waters between England and France. Those rules outlaw neoprene wetsuits and contact with a support boat. Nyad wore a full non-neoprene bodysuit, gloves, booties and a silicone mask at night, when jellyfish are a particular problem, and removed the suit once she got over the reef on her approach to Key West.

According to Nyad’s team, she finished the swim Monday afternoon after roughly 53 hours in the water, becoming the first to do so without a shark cage. It was her fifth try, an endeavor apparently free from the boat troubles, bad weather, illnesses and jellyfish encounters that have bedeviled Nyad and other swimmers in recent years.

Nyad’s progress was tracked online via GPS by her team, and some critics say they think information is missing.

Many wonder about a roughly seven-hour stretch when Nyad apparently didn’t stop to eat or drink, recalling her 2012 attempt when she got onto the boat for hours during rough weather. Nyad eventually got back into the water to try finishing, but her team was criticized for delaying the release of that information to the public.

Malinak said the hours-long spike in Nyad’s speed after 27 hours of swimming is particularly questionable — she went from her normal pace of roughly 1.5 mph to more than 3 mph, then slowed down again as she approached Key West.

Nyad’s spokeswomen did not immediately return telephone calls this weekend, but her navigator and Janet Hinkle, one of the official observers for the swim, told the AP that Nyad didn’t cheat.

Navigator John Bartlett said the increased speed was due to the fast-moving Gulf Stream working in her favor, nothing more.

“At some points we were doing almost 4 miles an hour,” Bartlett said. “That’s just the way it works. If the current is in your favor at all, that explains it.”

The data collected by Bartlett and two observers will be submitted to three open-water swimming associations and the Guinness World Records for verification, Bartlett said.

An oceanographer not affiliated with Nyad’s team said the swimmer couldn’t have picked a more perfect current to get from Havana to Key West.

Mitch Roffer of Melbourne-based Roffer’s Ocean Fishing Forecasting Service Inc. said he got an email questioning whether Nyad’s swim was a hoax, so he decided to look at the charts for himself. What he saw convinced him that she could do it.

“Many times that current runs west-east and you’re constantly fighting the current if you’re swimming north. In this case, it was in the shape of an S, and the angle was almost exactly from Havana to Key West,” Roffer said.

Janet Hinkle, a Key West boat captain and acquaintance of Nyad’s, was called to be an observer for the swim when Steve Munatones, a former U.S. national open-water coach, was unable to make it. “I can say unequivocally she swam every stroke without question,” Hinkle said.

Critics have said Hinkle was too close to Nyad to be an independent observer of her swim. Hinkle has in the past helped Nyad by providing housing for her when the swimmer stayed in the Florida Keys, but she said she remained on the periphery of Nyad’s team. “I think anyone who knows me knows me as a person of high integrity. I believe that’s why Diana asked me, and I took my job very seriously,” Hinkle said. “She was giving her all and I would give her my best.”

Since none of the various open-water swimming associations dictate how someone should swim from Cuba to Florida — officially accomplished only by Nyad and Susie Maroney, who used a shark cage — Nyad just had to follow generally accepted rules about not getting out of the water or using equipment such as fins.

Australian Chloe McCardel followed English Channel rules in her attempt to swim the Florida Straits in June. She had to be pulled from the water after 11 hours after being stung jellyfish.

“Generally the rules are: You walk in, you swim across and you walk out, and you do it under your own power,” said Munatones, who consulted with Nyad for this swim and observed her attempts in 2011 and 2012.

“To put that on is like putting on a wedding gown in the ocean,” he said. “It’s different from the English Channel rules, but the water is different from the English Channel.”

To many, it seems Nyad hasn’t exactly endeared herself to those in the marathon swimming community. Some consider her primarily concerned with gaining the spotlight instead of helping others advance the sport.

At her post-swim news conference on Tuesday, Nyad admitted that she had not been rooting for McCardel and that she was miffed some members of her team would jump ship to work for a competitor.

McCardel said she was disappointed to hear Nyad call those crew members “traitors.”

“One of the greatest things, I believe, about international marathon swimming is how people across the world support crew for and mentor each other. I wouldn’t change this aspect of our sport for the world!” McCardel posted on her Facebook page.